According to the prior art, a number of mixing elements are employed for carrying out fast reactions in a continuous procedure. A distinction may be made here between dynamic mixers, such as stirrers, turbines or rotor-stator systems, static mixers, such as Kenics mixers, Schaschlik mixers or SMV mixers, and jet mixers, such as nozzle mixers or T mixers [2-4].
For rapid mixing of starting substances in rapid reactions with undesirable secondary or side reactions, nozzle mixers are preferably employed.
In jet or nozzle mixers, one of the two starting components is atomized into the other components at a high flow rate (cf. FIG. 1). In this case, the kinetic energy of the stream (B) sprayed in is substantially dissipated behind the nozzle, i.e. is converted into heat by turbulent breakdown of the stream into eddies and further turbulent breakdown of the eddies into ever smaller eddies. The eddies contain the particular starting components, which are present side-by-side in the fluid balls (macromixing). A small degree of mixing by diffusion indeed occurs at the edges of these initially larger structures at the start of the turbulent breakdown of the eddies. However, complete mixing is achieved only when the breakdown of the eddies has progressed to the extent that, when eddy sizes of the order of magnitude of the concentration microdimension (Batchelor length) [5, 6] are reached, the diffusion is rapid enough for the starting components to be mixed completely with one another in the eddies. The mixing time required for complete mixing depends substantially on the specific energy dissipation rate, in addition to the substance data and the geometry of the apparatus.
The mixing processes in the mixers according to the prior art which are often used are in principle similar (in dynamic mixers and static mixers the eddies are also additionally divided mechanically, although as a rule with substantially lower specific energy dissipation rates). This means that in the mixers used according to the prior art, the time for breakdown of the eddies always elapses before complete mixing by diffusion. For very fast reactions, this means that either very high energy dissipation rates must be established, in order to avoid undesirable side and secondary reactions, or, in the case of reactions with even higher rates of reaction, the corresponding reactions are not carried out to the optimum, i.e. are carried out only with the formation of by-products or secondary products.
On the basis of this prior art, the object of the invention is to provide a process and a device with which mixing takes place rapidly and the formation of secondary products or by-products is suppressed or reduced. The achievement here must be that the educts are mixed homogeneously with one another so that, within the shortest time, local and time-related over-concentrations of the educts no longer occur. In the case of fluids which react chemically with one another, complete reaction of the fluids is to be achieved. If required, the heat of reaction should also be removed or supplied effectively and as rapidly as possible.